Search Images Maps Play YouTube News Gmail Drive More »
Sign in
Screen reader users: click this link for accessible mode. Accessible mode has the same essential features but works better with your reader.

Patents

  1. Advanced Patent Search
Publication numberUS4679889 A
Publication typeGrant
Application numberUS 06/793,654
Publication dateJul 14, 1987
Filing dateOct 31, 1985
Priority dateMay 24, 1985
Fee statusPaid
Also published asUS4605278
Publication number06793654, 793654, US 4679889 A, US 4679889A, US-A-4679889, US4679889 A, US4679889A
InventorsJack Seidler
Original AssigneeNorth American Specialties Corporation
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Solder-bearing leads
US 4679889 A
Abstract
The present invention relates to a solder-bearing lead for attachment to a contact pad on a printed circuit board or like substrate, or for mounting a circuit component on a substrate, suitable for being continuously stamped from a thick strip of metal at high speed, with an improved arrangement for holding the solder mass to provide the necessary solder for a soldered joint, without weakening the lead. Instead of retaining the solder mass by means of a finger struck from the elongated body of the lead (which for narrow leads might only weakly retain the solder and also weaken the lead by unduly reducing its already small cross-section), the solder mass is retained by one or more pairs of integral tabs or ears initially extending laterally from the elongated blank body, and then bent to form a solder-retaining channel in which the tabs may stake the solder.
Images(5)
Previous page
Next page
Claims(12)
What is claimed is:
1. A solder-bearing lead adapted to be soldered to a conductive surface, comprising:
an elongated strip-like body portion,
said body portion having on at least one edge thereof a pair of spaced laterally extending tabs defining an opening therebetween,
said pair of tabs being bent substantially perpendicular from the body portion strip to form therebetween part of a channel with said body portion forming a floor for said channel,
a solder mass in said channel and bordered by said pair of tabs,
said tabs being bent inwardly of said channel to retain said solder mass therein.
2. A solder-bearing lead as in claim 1, wherein said solder mass has a dimension extending away from said body portion at least as great as the extent of said tabs, whereby said solder mass extends flush of outwardly from said channel and may be placed in direct contact with the conductive surface to which said lead is to be soldered, while spacing said tabs from said surface, and upon melting said solder mass, said tabs are permitted to be or move into contact with said conductive surface to make electrical contact therewith and to be retained in such contact upon re-solidification of said solder mass.
3. A solder-bearing lead as in claim 2, wherein said solder dimension is substantially equal to the projection of said tabs away from said body portion.
4. A lead as in claim 1, wherein said tabs and solder mass are adjacent one end of said lead,
the other end of said lead being formed as an electrical element, whereby said electrical element may be surface-mounted on said conductive surface by juxtaposing said solder mass to said surface, melting said solder, and re-solidifying said solder.
5. A lead as in claim 4, wherein said element is a circuit board edge clip.
6. A lead as in claim, 4, wherein said element is a pin-receiving connector contact.
7. A lead as in claim 4, wherein said element is a circuit board connector contact.
8. A lead as in claim 1, further including a spring finger integral with said lead body portion and positioned opposite to said solder mass to form a clip arrangement for a circuit board or the like.
9. A terminal for a circuit component for surface mounting it on a substrate having a conductive area, comprising a solder-bearing lead as in claim 1, where said tabs are located adjacent one end of said lead and in a position to be juxtaposed to said conductive area of said substrate.
10. A method of forming a solder-bearing lead adapted to be soldered to a conductive surface, comprising the steps of:
forming a flat elongated strip-like blank with a body portion,
said blank having on an edge of said body portion a pair of laterally extending spaced tabs with an opening therebetween,
bending said pair of tabs on said one edge of said body portion substantially perpendicularly of said body portion,
placing a solder mass in said tab opening and on said body portion, and
staking the edges of said tabs with said solder mass to secure said solder mass to said body portion.
11. A method as in claim 10, wherein said solder mass is substantially level with the tips of said tabs.
12. The method of claim 10, wherein said solder mass is depressed below the tips of said tabs.
Description

This application is a continuation-in-part of prior application Ser. No. 737,830, filed May 24, 1985 for "Solder-Bearing Leads", now U.S. Pat. No. 4,605,278.

BACKGROUND OF THE INVENTION

This invention relates to solder-bearing contacts, terminal elements and leads, particularly for use with multiple-contact connectors and electronic circuit boards, and for surface-mounted devices.

In the electronic equipment industry, an important necessity is the rapid and accurate assembly of leads, terminals and contacts with the contact pads of printed circuit boards or other substrates. For convenience of connecting such elements, it has previously been suggested to facilitate the soldering of their connection by securing a solder slug or mass to one of the elements so that, when positioned in engagement with the other element and heated, the molten solder will cover the adjacent surfaces of both elements to form when cooled a soldered joint providing both a mechanical coupling and an electrical connection between the elements. Various arrangements of solder-holding elements are disclosed in Seidler Pat. Nos. 4,120,558 and 4,203,648, in each of which a lead has a finger struck from it, for holding the solder mass to the lead.

However, as the art tends toward greater miniaturization in this field, there has been a reduction in the size of and spacing between the contact pads on printed circuit boards, for example, requiring corresponding reduction in the size and spacing of the leads for connection thereto.

SUMMARY OF THE INVENTION

It is a principal object of the present invention to provide a solder-bearing lead for attachment to a contact pad on a printed circuit board or like substrate, or for mounting a circuit component on a substrate, suitable for being continuously stamped from a thick strip of metal at high speed, with an improved arrangement for holding the solder mass to provide the necessary solder for a soldered joint, without weakening the lead. Instead of retaining the solder mass by means of a finger struck from the elongated body of the lead (which for narrow leads might only weakly retain the solder and also weaken the lead by unduly reducing its already small cross-section), the solder mass is retained by integral tabs or ears initially extending laterally from the elongated blank body, and then bent to form a solder-retaining channel in which the tabs may stake the solder. This provides a secure mechanical attachment for the solder mass to the lead, to provide each lead with the necessary supply of solder at a proper location for its attachment to and electrical bonding to another conductive surface. This is particulrly desirable for surface-mounted devices on printed circuit boards or other substrates. In addition, this arrangement can be made by automatic progressive stamping by simple and efficient steps, at high speed.

The invention accordingly comprises an article of manufacture and method of fabrication possessing the features, properties and relation of elements exemplified in the embodiments described in the following, the scope of the invention being set out in the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

With particular reference to the drawings, several forms of the invention are shown in the various figures, where like reference characters designate like parts throughout the several views. In the drawings,

FIG. 1 shows a plan view of a strip formed into flat blanks for use in making one embodiment of the improved lead of the invention;

FIG. 2 is a plan view of one of the leads made from the blank of FIG. 1, formed to hold a solder mass;

FIG. 3 is a sectional elevation view of the arrangement of FIG. 2, showing the solder mass positioned between retaining tabs;

FIG. 4 shows the arrangement of FIG. 3 with the retaining tabs staked into the solder mass;

FIG. 4A shows an alternative arrangement to that of FIG. 4;

FIG. 5 shows a side sectional elevational view of an edge clip solderable connector for a printed circuit board or the like, made from the blank of FIG. 1;

FIG. 6 shows a plan view of a modified form of the stamped blank for another embodiment of the invention;

FIG. 7 shows a side elevation view of an edge clip for a printed circuit board, which may be formed from the blank of FIG. 6, and is adapted for surface mounting on a substrate;

FIG. 8 shows a side elevation view of a partially formed blank for the embodiment of FIGS. 6 and 7;

FIG. 9 shows a transverse elevation sectional view of a vertically mounted pin-receiving connector adapted for surface mounting on a substrate by use of the solderable lead of the present invention;

FIG. 10 is a transverse elevation sectional view of another connector for a vertically mounted printed circuit board, adapted to be mounted on a substrate by use of the solderable lead of the present invention;

FIG. 11 shows a plan view of an alternate form of strip of blanks useful in connection with the previous embodiments of the present invention for economy of material and providing closer spacing of the leads;

FIG. 12 shows a side elevational view of a connector arrangement according to the invention for joining two printed circuit boards or the like in coplanar alignment;

FIG. 13 shows a plan view of a modified form of stamped blank for another embodiment of the invention;

FIG. 14 shows a side elevation view, partly in cross-section, of a clip for a circuit board or the like, made from the blank of FIG. 13, and adapted for surface mounting the circuit board on a substrate;

FIG. 15 shows a plan view of still another embodiment of a stamped blank constituting a form of the invention;

FIG. 16 is a side elevation view, partly in section, of another embodiment of a device similar to FIG. 14, showing a different form of solderable surface mounting;

FIG. 17 is a fragmentary plan view of a modification of the invention having a single pair of ears for retaining the solder mass; and

FIG. 18 is a perspective view of another form of terminal connector according to the invention.

DESCRIPTION OF PREFERRED EMBODIMENTS

Referring to the drawings, FIG. 1 illustrates a stamped strip having a sequence of individual blanks 10 for the leads of the invention, formed by stamping from a conductive strip (as of beryllium copper or like resilient and conductive material), with the individual lead blanks 10 extending between a pair of carrier strips 12. Strips 12 may carry sprocket holes 14 for indexing the lead blanks step-by-step through subsequent progressive stamping steps for forming the blanks into final form.

Each lead is formed of an elongated body section 16 of length appropriate for the intended use of the finished lead, and having oppositely extending tabs 18 on its lateral edges, in the form of sloping extensions with a gap 20 therebetween. The gap 20 is dimensioned to have a width substantially equal to the width of a solder wire to be laid therein, and a depth dimension somewhat less than the solder wire dimension, as will be seen. In addition, the body section 16 is slitted or cut to form a resilient finger 22. It will be understood that the tabs are not necessarily triangular in shape but may be rectangular or of other shape, preferably with straight edges extending transversely of the lead body.

For holding a solder mass or slug to the lead, in the forming process, the tabs 18 are bent out of the plane of the body section 16 into a position substantially perpendicularly, as shown in FIGS. 2 and 3, thereby providing a channel 24 having a "floor" formed by the body section 16, and sides formed by the edges of the tabs 18. Into this channel is laid solder, preferably as a wire 26. The wire 26 may be cut on either side of the body 16 an appropriate distance from the tabs 18 to supply the desired amount of solder for the soldering operation. The solder wire 26 preferably closely conforms to the width of the channel 24, and may be flush with or extend somewhat above the channel 24, as seen in FIG. 3, so that the solder has an exposed surface 28. After the solder wire is positioned within channel 24, and either before or after it is cut into the appropriate section lengths, the tabs 18 may be bent inwardly to stake the solder mass 26 in place and thereby retain it physically connected to the body section 16, as shown in FIG. 4.

FIG. 4A shows an alternative configuration to that of FIG. 4, where the solder mass 26 is pushed into the channel 24 to nearly fill the channel, and to offer a lower profile so that on juxtaposition to the element to which the lead is to be soldered, the tabs 18 will be closer to that element, to improve the reliability of soldering. The exposed surface 28 may have the solder mass flush with the tabs 18, or even slightly recessed into channel 24, as desired, so as to permit even closer contact, before soldering, between the retaining tabs and the corresponding element to which they are to be soldered.

With the solder mass projecting very slightly outwardly of the retaining tabs, upon insertion of the circuit board to be soldered into the gap between a pair of solder masses (or between one solder mass and a resilient opposed member as in FIG. 7), the insertion of the circuit board will serve to wipe off excess solder (which is relatively soft) and smear it over the adjacent portion of the contact pad, which will assist in obtaining a good solder joint.

It will be understood that this solder-retaining arrangement, depicted in FIGS. 2 to 4 and 4A, may be used in various applications in the electronics art, some of which are described below.

In one use, the blank 10 of FIG. 1 may be formed with a resilient finger 22. As seen in FIG. 5, the solder-bearing portion 30 of the lead is bent substantially at a right angle to the remainder of the body portion 16 and the spring finger 22 is positioned with a bend 32 opposite the solder mass 26. This provides a springy gap between the solder 26 and the bend 32 within which may be inserted a circuit board or other substrate 34, having a conductive area or contact pad 36 to which it is desired to solder the lead. The resilience of finger 22 serves to retain the lead in position on the circuit board 34 before the soldering is done, and as the solder melts upon application of heat, the finger 32 serves to allow the tabs 18 to move relatively toward and into contact with the conductive area 36, to provide good electrical contact between the lead and the conductive area 36 when the solder re-solidifies. In this application, the lead forms an edge clip for the circuit board 34, and the terminal end 38 of the lead may be suitably formed in a number of ways for connection to other equipment, such as being formed as a pin for insertion into a contact receptacle, or as a wire-wrap post termination, or as a further solderable arrangement, indicated below.

FIG. 6 shows a modified form of strip blank carrying a lead blank as a modification of FIG. 1. In this form each lead blank is provided with a second set of solder-retaining tabs 44. As shown in FIG. 7, the terminal portion 38 of the lead is formed with a solder-retaining arrangement 46 essentially the same as arrangement 30 of FIG. 5. However, in this instance, the tabs 44 are bent from the body portion 16 in a direction opposite to that of the tabs 18, as shown in FIG. 8, so that the terminal solder-retaining arrangement 46 may be used for surface mounting the circuit board 34 on a further substrate 40 for connection to a conductive area 41 on substrate 40.

In an alternate form (not illustrated), the tabs 44 may be bent in the same direction as tabs 18, in which case the terminal portion 38 of the lead, instead of extending to the left as seen in FIG. 7, would extend to the right.

The solder-retaining arrangement of the present invention may also be used as a terminal portion of other forms of leads, terminals, contacts, and connectors. Thus, as seen in FIG. 9, the solder-retaining arrangement 46 may be the terminal for a contact 50 of a multiple-contact connector where each contact 50 is in a channel 48 into which extends a spring finger 52 integrally formed with the contact 50, for mating contact with a pin when inserted into channel 48. FIG. 9 illustrates a cross-section of a dual row of pin-receiving receptacles, each formed as shown in FIG. 9. It will be understood that the same arrangement may be used for single-row or other multiple-row connectors, permitting surface mounting upon a substrate having conductive areas 56 to which the contacts 50 are to be soldered. While the channels 48 are shown in this instance as perpendicular to the substrate 54, suitable for a vertically oriented connector, other arrangements may be made by which the connector may be oriented horizontally or at other angles.

FIG. 10 illustrates use of the solder-retaining terminal arrangement 46 for surface mounting a circuit board connector 58 on a substrate 54. This figure shows a transverse cross-section of a multiple-contact circuit board edge-connector having a housing 62 in which are mounted spring contacts 60 for separable connection to contact pads on the circuit board when inserted. It will be obvious how the blanks for forming the leads and contacts of FIGS. 9 and 10 are formed. In each case, there will be tabs such as 44 or 18 bent outwardly from the body of the lead, the remainder of the lead being suitably formed for its intended purpose as in FIGS. 5, 7, 9 or 10.

As shown in FIG. 1, the blanks 10 formed into the multiple blank strip are generally side-by-side and in alignment. However, in some instances it may be desirable to place them closer together, as for automatic insertion into housings having closely-spaced channels, or for purposes of economizing on waste material. FIG. 11 shows how the blank leads 10 may be staggered on the carrier strip to place them more closely for this purpose.

FIG. 12 shows a form of the invention adapted for joining two printed circuit boards or substrates 64 in co-planar alignment. In this instance, the terminal body 110 is formed at each end with a solder-bearing and holding arrangement 119 formed by ears or tabs 118 similar to tabs 18 of FIG. 4. Each of these solder-holding arrangements 119 is adapted for soldering to a contact pad 66 of a respective substrate or printed circuit board 64. The contact body 110 joining the two solder-bearing portions 119 is bent at 120 and 122 to form two resilient portions 121, each cooperating with a solder-holding portions 119 to retain a substrate 64 therebetween during the soldering operation.

FIG. 13 shows another form of blank usable in another embodiment of the invention. In this instance, the terminal body 210 extending between the carrier strips 212 has three sets of ears or tabs 218 for the purpose of retaining three solder masses. This blank of FIG. 13 may be bent in the form of FIG. 14, so that two of the solder-retaining arrangements 219 straddle the substrate 224 for soldering to contact pads 226 thereon. The third solder-bearing arrangement 219' is adapted for surface mounting the substrate 226 and its connected terminal 210 to an additional substrate 228 having a contact pad 229 thereon, in evident manner.

FIG. 15 shows still another blank having two solder-holding arrangements 320 and 322 formed by solder-retaining tabs 318. In addition, a spring finger 322 may be cut or punched out from the center of the terminal body 310. As shown in FIG. 16, the solder-retaining arrangements 320 and 322, similar to those disclosed above, are adapted for soldering to the respective contact pads 326 of a substrate 324. The finger 322 may be used for surface mounting the entire arrangement on an additional substrate 328, having a contact pad 330, by being wrapped around a solder mass 332 by at least 180 to retain the solder mass 332 between the pad 330 and the terminal 322, pending the soldering operation.

While in each of the foregoing arrangements the solder mass exemplified by 26 or 126 or the like has been shown as held by two sets of ears or tabs 218, one set being bent up from each edge of the main lead body, it will be understood that at some instances a single pair of tabs 418 may be used as shown in FIG. 17. This will have the advantage of permitting use of a narrower blank with a saving of material, where satisfactory retention of the solder slug is obtainable.

FIG. 18 shows a perspective view of a special contact 511 to connect a substrate to a second substrate by surface mounting. The contact 511 is carried on a carrier strip 531, which may be cut away (together with any unneeded section of the contact body) upon or prior to attachment of contact 511 with a substrate. In this structure, a spring finger 510 cooperates with a solder-bearing arrangement 512 of any of the types indicated above, to form a gap therebetween to receive a substrate which carries contact pads. A lower contact pad on such substrate may be soldered to the contact 511 by means of the solder arrangement 512 while the upper spring finger 510 serves to clamp the solder-holding arrangement 512 in position during the soldering operation. This spring finger 510 may also be used to connect a contact pad or circuit portion on the upper side of the substrate to the contact 511 and to the lower contact pad to which it is soldered by the solder arrangement 512.

A second solder arrangement 514 is supplied, which may be of any of the types described above, and permits the entire arrangement of substrate and terminal to be surface mounted and soldered to an additional substrate, generally as shown in FIGS. 14 and 16.

FIG. 18 also shows a modified arrangement for holding the solder slug 526 between the ears 518 in a fashion where the solder 526 is essentially flush with the edge of the tabs 518, to facilitate contact between the tabs 518 and the contact pad to which it is to be soldered. It will be understood that this arrangement also may be used in place of those shown in FIGS. 4 and 4A.

It will be understood that the solder-retaining arrangement of the present invention is suitable for many other applications, where it will have the advantages discussed above as well as others. Accordingly, the above embodiments are to be deemed illustrative only and the present invention is defined by the appended claims.

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US4120558 *Aug 15, 1977Oct 17, 1978North American Specialties CorporationSolder bearing terminal
US4203648 *Aug 23, 1978May 20, 1980North American Specialties Corp.Solder bearing terminal
US4503609 *Oct 29, 1982Mar 12, 1985At&T Technologies, Inc.Low-insertion force method of assembling a lead and a substrate
US4596439 *Aug 5, 1985Jun 24, 1986Illinois Tool Works Inc.Sheet metal terminal
US4597628 *Sep 19, 1985Jul 1, 1986North American Specialties CorporationSolder bearing clip
US4605278 *May 24, 1985Aug 12, 1986North American Specialties CorporationSolder-bearing leads
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US4872846 *Jul 21, 1988Oct 10, 1989Clark Thomas CSolder containing electrical connector and method for making same
US4883435 *Dec 7, 1987Nov 28, 1989North American Specialties CorporationSolder-bearing terminal pin and lead
US4900279 *Apr 24, 1989Feb 13, 1990Die Tech, Inc.Solder terminal
US4984359 *May 19, 1989Jan 15, 1991Amp IncorporatedMethod of making a solder containing electrical connector
US5052954 *Oct 3, 1989Oct 1, 1991North American Specialties CorporationSolder-bearing terminal pin and lead
US5139448 *Apr 16, 1991Aug 18, 1992North American Specialties CorporationSolder-bearing lead
US5441429 *Aug 18, 1993Aug 15, 1995North American Specialties CorporationSolder-bearing land
US5571034 *Jan 20, 1995Nov 5, 1996North American Specialties CorporationMethod of making an array of electrical components with leads attached and the product thereof
US5875546 *Oct 7, 1996Mar 2, 1999North American Specialties CorporationMethod of forming solder-holding clips for applying solder to connectors
US6099365 *Dec 29, 1997Aug 8, 2000North American Specialties CorporationSolder-holding clips for applying solder to connectors or the like
US6116921 *Feb 16, 1998Sep 12, 2000The Whitaker CorporationElectrical connector having recessed solderball foot
US6210182Jun 11, 1996Apr 3, 2001Berg Technology, Inc.Low cross talk and impedance controlled electrical connector
US6217348 *Aug 9, 1999Apr 17, 2001Hon Hai Precision Ind. Co., Ltd.Electrical connector
US6261136Jul 10, 2000Jul 17, 2001Die Tech, Inc.Edge clip terminal
US6300579 *Apr 28, 1999Oct 9, 2001Kitagawa Industries, Co., Ltd.Grounding terminal and mounting structure of the same on a printed circuit board
US6319025 *Jul 17, 1998Nov 20, 2001Nec CorporationSurface installing type connector
US6402574Dec 29, 1997Jun 11, 2002North American Specialties CorporationSolder-holding clips for applying solder to connectors or the like
US6465738Sep 13, 2001Oct 15, 2002Kitigawa Industries Co., Ltd.Grounding terminal and mounting structure of the same on a printed circuit board
US6494754Jan 2, 2002Dec 17, 2002North American SpecialtiesSolder-holding clips for applying solder to connectors or the like
US6544045 *Nov 1, 2000Apr 8, 2003Fci Americas Technology, Inc.Surface mounted right angle electrical connector
US6674018Sep 13, 2001Jan 6, 2004Kitigawa Industries Co., Ltd.Grounding terminal and mounting structure of the same on a printed circuit board
US6939173 *Dec 10, 1998Sep 6, 2005Fci Americas Technology, Inc.Low cross talk and impedance controlled electrical connector with solder masses
US6969286Oct 20, 2004Nov 29, 2005Samtec, Inc.Connector having improved contacts with fusible members
US6979238Jun 28, 2004Dec 27, 2005Samtec, Inc.Connector having improved contacts with fusible members
US7052337Jul 1, 2005May 30, 2006Samtec, Inc.Connector having improved contacts with fusible members
US7125293Jul 1, 2005Oct 24, 2006Samtec, Inc.Connector having improved contacts with fusible members
US7159312Oct 20, 2004Jan 9, 2007Samtec, Inc.Connector having improved contacts with fusible members
US7178232Oct 20, 2004Feb 20, 2007Samtec, Inc.Connector having improved contacts with fusible members
US7837522Nov 12, 2009Nov 23, 2010Samtec, Inc.Electrical contacts with solder members and methods of attaching solder members to electrical contacts
EP1717912A1 *Jun 11, 1996Nov 2, 2006FciLow cross talk and impedance controlled electrical connector
WO1995020250A1 *Jan 25, 1995Jul 27, 1995North American SpecialitiesSmart card connector
Classifications
U.S. Classification439/876, 439/83, 439/637, 29/876
International ClassificationH05K3/34, H01R43/16, H01R12/04, H01R4/02, H01R12/32, H01R9/00, H01R43/02
Cooperative ClassificationH01R2107/00, H01R24/60, H01R12/52, H01R12/57, H05K2201/10984, H05K3/3405, H01R43/02, H01R43/16, H05K2201/10386
European ClassificationH01R12/57, H05K3/34B, H01R43/16
Legal Events
DateCodeEventDescription
Mar 19, 2002CCCertificate of correction
Jan 11, 1999FPAYFee payment
Year of fee payment: 12
Jan 9, 1995FPAYFee payment
Year of fee payment: 8
Jan 7, 1991FPAYFee payment
Year of fee payment: 4
Oct 31, 1985ASAssignment
Owner name: NORTH AMERICAN SPECIALTIES CORPORATION, 120-12 28T
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:SEIDLER, JACK;REEL/FRAME:004478/0419
Effective date: 19851028